Add some advice to doxygen docs.
Implement HTTP Basic Authorization for sproxyd

and make the function that creates the Authorization header shared
between the CDMI and sproxyd backends.
Unit test dpl_set_log_func()
Remove extraneous \n from DPL_LOG() calls
Capture SSL errors in the log function too

instead of dumping them to stderr.
Add a trivial fake sproxyd server for testing

- extremely simple HTTP server
- can be started and stopped from test code
- server internal state is exported to a mmap'd file
- test code can examine server internal state (useful
  for verifying that Droplet is generating correct HTTP)
Move some useful functions into testutils.c

to make them available to other tests, not just the profile tests.
Move the sproxyd test into its own .c file

and modify it to do less in the test function and more in fixtures.
This will make it easier to write more tests like it.
Remove unnecessary printf in httpreply.c
Handle ECHILD in toyserver_wait()

because that actually happens.
Make toyserver verbosity configurable

instead of hardcoded to "loud".
Unit test HTTP Basic authorization in sproxyd.
Merge remote-tracking branch 'gnb/docs2' into merge_http_auth